This proposal will investigate human lymphocyte subpopulations and their alterations in the rheumatic diseases and other clinical conditions. Specifically lymphocytes with surface alpha-fetaprotein, IgG-Fc /IgM-Fc receptors, and receptors for viral antigens (rubella, rubeola, C-type viruses) will be investigated. Mitogen hyporesponsiveness in Hodgkin's disease and the rheumatic diseases will be studied using glass adherent cell depletion. The possibility that immunologic suppression may be mediated by prostaglandin produced by leukocyte subpopulations will be investigated by the quantitation of prostaglandin synthesis and the effect of prostaglandin synthetase inhibition by indocin on lymphocyte responsiveness.